In the following description and claims the term "distribution member" refers to a rotatable outlet deflector nozzle adapted for emitting the irrigation water, while establishing reactionary force components for rotating thereof. Such distribution members are at times referred to also as "rotatable or rotary distributors", "swivels", "reaction swivels", etc.
Typically, rotary sprinklers are divided into two categories, namely sprayers and sprinklers. Sprayers, typically have essentially low flow rate and short irrigation range. The high speed of revolution of the distribution member causes atomization of the water jet into fine spray, which lacks the energy to reach longer distances. The second category, referring to sprinklers, is suitable for use with essentially high-flow rates and provides higher irrigation range than sprayers.
It is well known that excessive irrigation of plants and in particular of plantlets, is harmful and even fatal for plants. In particular, the problem of excessive irrigation occurs in greenhouses, where ventilation and evaporation are relatively low.
Some rotary sprinklers comprise a bridging member for supporting the rotary distribution member at its upper end. However, the bridging member in such sprinklers is an obstacle for the water emitted from the distribution member, whereby a full circular path is not obtained. Even more so, in many designs of sprinklers dripping occurs below the sprinkler which without suitable draining means might be harmful for the plants.
In another type of rotary sprinkler there is no bridging member. However, in such sprinklers the rotary distribution member is mounted over a rotary shaft rotating within the nozzle, the lower end of the shaft being connected to a drive mechanism, typically being a hydraulic turbine or ball driven mechanism.
The drawback of such an arrangement is that it requires the additional drive mechanism, which generates some friction, resulting in some loss of revolution speed of the distribution member. Even more so, such drive mechanisms are vulnerable to mechanical faults caused, in particular, as a result of dirt or insects entering into the drive mechanism.
It is thus an object of the present invention to provide a new and improved rotary sprinkler, being a combination of a sprayer and a sprinkler, wherein a relatively fine water spray is emitted to an essentially high range and wherein the above referred to drawbacks are essentially reduced or overcome.